The present invention relates to a process for forming a luminous layer that absorbs and emits light, on a metallic or non-metallic plate having a surface coated with a photo-catalytic titanium dioxide layer. The plate having the luminous material layer provides photo-catalytic activity and is formed with a metallic compound layer. This plate exhibits the characteristics of deodorization, antibiotic activity, and prevention of ambient contamination.
This invention relates to a surface treatment process for forming a base metal or non-metal having a light absorbing material present and metallic compound layer having photocatalytic activity.
Methods of deodorization are known in which an apparatus or a piece of equipment is used for exhausting or masking odors. The removal of molds by means of chemicals is generally performed by selecting an appropriate chemical according to the kind of mold.
Odors and molds are attributable to microorganisms, such as bacteria, yeasts and molds, and animal and plant cells. Accordingly, the attempt to deodorize and prevent molds and fouling can, in principle, be considered as the destruction of these cells, i.e., sterilization. Known methods of sterilization include heating, irradiation with ultraviolet or other radioactive rays, cell destruction by means of ultrasonic waves, electric sterilization, gas sterilization, and sterilization using chemicals including antibiotics. In addition, a sterilization method using fine particles of a photocatalyst is also known. Photocatalysts such as titanium dioxide are known to exhibit photocatalytic function by means of a light of a specific wavelength and possess deodorizing and antimold functions through their oxidizing action.
Conventionally, titanium dioxide, iron oxide, tungsten oxide, silicon oxide and the like, or such metals optionally with second metal, such as platinum, thereon for the purpose of improving the catalytic function are used as photocatalysts. To make use of the deodorizing and antimold functions, such metals are normally pulverized into fine particles to form a fixed film on a surface, or the fine particles are used by being dispersed in an object to be treated.
Various studies have been made regarding methods of imparting deodorizing and antimold functions to materials by making use of the photocatalytic function, however particles are troublesome to handle as materials. Known fixed films have only been used experimentally, and their strength is not sufficient, and the fabrication of photocatalytic materials into thin films has been industrially difficult, and has not yet been put into commercial use.
It is an object of the present invention to provide a material having a titanium dioxide layer exhibiting the characteristic of photocatalytic activity in addition to a light absorbing material, which provides the base light for photocatalytic activity of titanium dioxide.
A further object of the present invention is to provide a material which exhibits the characteristics of deodorization, antibiotic activity and prevention of ambient contamination in darkness after a short exposure to light irradiation.
It is also an object of this invention to provide a metal surface with a titanium dioxide coating having photocatalytic activity which can be used in applications where the base metal is useful, including construction materials, filtration systems, food processing equipment and containers, garbage or trash containers, and the like.
This invention provides a material (metallic or non-metallic) having a surface coated with a metallic compound which exhibits photocatalytic activity in addition to the presence of a light absorbing material. The materials to be coated with the metallic compound advantageously are metals, plastics, composites, paper and the like. Advantageously the metallic compound layer is formed of anatase TiO2.
The photocatalytic activity of the present inventive coated material is useful in any application in which the base material is useful, including in construction materials, filtration systems, food processing equipment and containers, garbage or trash containers, and the like.